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A023588 a(n) = sum of exponents in prime-power factorization of 2*prime(n)-1. 0
1, 1, 2, 1, 2, 2, 2, 1, 3, 2, 1, 1, 4, 2, 2, 3, 3, 2, 2, 2, 2, 1, 3, 2, 1, 2, 2, 2, 2, 4, 2, 3, 3, 1, 4, 2, 1, 3, 3, 3, 3, 2, 2, 3, 2, 1, 1, 2, 2, 1, 3, 3, 2, 2, 4, 4, 2, 1, 2, 3, 2, 4, 1, 4, 4, 2, 1, 1, 4, 2, 3, 2, 1, 2, 1, 4, 3, 2, 3, 2, 4, 2, 3, 2, 1, 3, 3, 2, 2, 3, 2, 3, 2, 3, 1, 3, 3, 2, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..99.

FORMULA

a(n) = A001222(A076274(n)). - R. J. Mathar, Mar 10 2011

MATHEMATICA

Array[Plus@@Last/@FactorInteger[2*Prime[ # ]-1]&, 6! ] (* Vladimir Joseph Stephan Orlovsky, Feb 28 2010 *)

CROSSREFS

Sequence in context: A067148 A035228 A035164 * A175242 A225843 A001227

Adjacent sequences:  A023585 A023586 A023587 * A023589 A023590 A023591

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 22 06:17 EST 2018. Contains 299430 sequences. (Running on oeis4.)